Dr. Matthew Edlund, MD, MOH

Your different states of consciousness (1/3/11)

January 3, 2011

Coma and Wakefulness – Anesthesia Creates Coma, not Sleep

Does anesthesia put you to sleep? A long review of what really happens in anesthesia, published recently in the New England Journal, points out what cognitive scientists have known for a long time – our usual layman’s terms give little credence to the extraordinary variety of human consciousness. For us, rather than levels of consciousness, there are many different states.

One of them is coma – unresponsiveness to outside stimuli, plus a brain that can’t do much beyond the amazingly complicated process of keeping you alive. It turns out that anesthesia is a lot closer to coma than many people thought. More bizarrely, sleeping pills like ambien (zolpidem) seem to ape parts of this descent into coma.

So here’s (with apologies to scientists and philosophers) a consumer’s guide to some common states of consciousness you may see in your daily life:

States of Consciousness You Will See

1. Stage 1 sleep proves that states of consciousness not only run fluidly into each other, but are often unrecognized.

Many people have microsleeps of 10-30 seconds at a time, especially when driving late at night. Often they are not perceived, not even as blips of changed consciousness – with sometimes fatal results. Akerstedt’s studies of Swedish train conductors showed they routinely fell asleep at night standing up – with their eyes open. (Fortunately for us, professional truck drivers appear pretty good at knowing when microsleeps are going to hit.)

A Henry Ford Hospital study by Rosenthal et al. had people fall into stage 1 sleep for 10 minutes. When it was over, fully half thought they were awake the whole time.

They were not. Some were snoring away. They had no conscious activity.

They just thought they were awake – and argued vigorously with the researchers, even when shown videotapes of what they had done.

Think of it this way – the brain is a bunch of “kludges”, engineering systems jerry built to do something like vision that through evolution got involved in 15 varied activities of which they are sometimes necessary but usually insufficient parts. Brains areas get used multiply. It’s kind of like thinking of a plywood two by four as part of a table, the base of a floor, an actor’s weapon, a mattress elevator, a plane for writing, a carved signboard, a room divider, a toy, and who knows what else.

To get to stage 1 sleep you need to get dozens of different kludges to simultaneously work together. It’s more like putting nine separate orchestras in different sections of the Houston Astrodome, some in the boxes, others on the field, a few in the washroom, and getting them to play the same note at the same time at the same rhythm.

If that doesn’t happen, you might jerk upward as do students in high schools all over the country do throughout the morning, or early commuters on trains or – maybe even you (hopefully not while reading this sentence.)

2. Delirium – fluctuating states of consciousness confuse the heck out of people, but are common. You often see it in elderly people, who will shift suddenly from talking knowledgeably about the stock market to forgetting your name or where they are. However, intoxication, generally with alcohol but now more and more commonly with prescription medications, may produce the same effect.

New Year’s Eve is one arena where you can watch many different examples of mild delirium.

3. Early morning wakefulness.Getting up is hard to do, as your cold brain tries to warm up and notice what’s going on. This is essentially a state somewhere between stage 1 sleep and getting awake, and can lapse in-between the two for many minutes before people stop hitting the snooze control and actually attempt to get out of bed.

Standing up, moving, and seeking sunlight are great ways to start to get awake. However, full alertness may still be hours away – another reason to keep moving and get light.

4. REM sleep – commonly thought of as dream sleep (we actually can dream in any stage of sleep) REM is a bizarre form of consciousness where temperature controls disappear and the many kludges of the brain seem to wildly communicate with each other to take the new information of the previous day, anneal it with old memories, and make useful information the body can then learn from while it remakes itself. A time of much rewiring and physical rejiggering of memory and thoughts, notwithstanding peak testosterone production, the conscious fragments of what REM produces are what we call complex dreams.

5. Deep sleep – often apparently only in the first part of the night, deep sleep is as close to coma as we normally get. Also a time of massive rewiring, deep sleep is when growth hormone production takes place.

In deep sleep you literally grow, though you may not be able to be awakened for two or more minutes into anything resembling wakefulness – thus the term deep sleep. Oddly, deep sleep is where sleepwalking and other funky confusional arousals occur. Much of their bizarreness lies in their not being remembered at all – because you’re in deep sleep. Many confusional arousals occur because the circuitry turning off physical movements fails.

Getting Awake

Consciousness is not just a bunch of different levels – it’s a group of different states.

But everything is fluid. Just as we move in and out of alert wakefulness, ranging from paralyzed semi-conscious television watching to creative peaks when engaged in the state called flow, what we remember and what we don’t involves many different shifts of consciousness.